Food Chemistry Advances (Jun 2024)
Investigation the optical properties of Palestinian olive oils for different geographical regions by optical spectroscopy technique
Abstract
Olive oil serves as a significant source of income for Palestinian farmers, both on a national and international scale. This study focuses on assessing the quality and identifying key compounds in olive oils from different regions, employing UV–visible absorption and photoluminescence spectroscopy. UV-visible absorbance analysis uncovered specific absorption bands associated with chlorophyll, and carotenoids. Additional measurements at 232, 266, 270, and 274 nm, along with K values calculations, indicated that the oils from these regions are predominantly extra virgin. Photoluminescence measurements in two and three dimensions revealed three distinct emission bands. The first, peaking at 320 nm, was linked to polyphenols, the second, a red emission at 670 nm, to chlorophyll, and the third, spanning 400–580 nm, to oxidation products and vitamin E. When examining olive oil adulteration with sunflower oil, both absorption and photoluminescence data exhibited a significant reduction in peak intensity for chlorophyll, carotenoids, and polyphenols. Additionally, this research explored pigment content in olives from various geographic origins, finding that the ratio values align with ideal standards for Extra Virgin Olive Oil (EVOO) and provided insights into the percentage of lutein within the carotenoid composition.
